1. Field of the Invention
The present invention relates to an image stabilizer and an image capturing device, and particularly relates to an optical image stabilizer and an image capturing device using the same.
2. Description of Related Art
Image capturing devices, such as digital video camera (DVC) and digital still camera (DSC) include various functions for users to capture images of objects. When users use small-sized portable device such as digital video camera or digital still camera to capture images of objects, the vibration of the camera would pose a negative impact on the images. For ensuring the stability of the images, various techniques for detecting and compensating the vibration of the cameras are adopted. According to different compensating methods, image stabilizers can be divided into three types: electronic image stabilizer (EIS), optical image stabilizer (OIS) and digital image stabilizer (DIS).
In general, an optical image stabilizer detects the vibration value of a camera by accelerometer, gyroscope, etc., and drives the moving platform generating a displacement in order to move the lens for compensating the vibration value of the camera. When the moving platform generates the displacement, a sensor is used to sense the displacement value of the moving platform and determine whether the displacement is enough to compensate the vibration value of the camera in order to decide either to continue or to stop driving the moving platform to move. In detail, a plurality of sensors are fixed on the moving platform, and a plurality of the magnetic elements corresponding to the sensors are disposed on the camera. When the moving platform moves, the variation of the magnetic force applied to the corresponding sensor by each magnetic element can be sensed for measuring the displacement value of the moving platform along a plurality of directions, for example, horizontal direction, vertical direction, etc. The disposition of the magnetic elements described above increases the manufacturing cost and takes up the inner space of cameras. If the layout of the magnetic elements can be simplified, the manufacturing cost and the layout space can be effectively decreased. Furthermore, the sensing range of the sensors is limited, therefore, how to effectively increase the sensing range thereof has become an important subject for the design of optical image stabilizers.